The lipid raft-linker gene Raftlin-2 is expressed in migrating neural crest cells

Transient plasma membrane domains called lipid rafts have emerged as important regulators of signal transduction. These territories are formed by lipid-lipid and lipid-protein interactions, and these local interactions can be scaffolded by resident lipid raft organizing protein family members. While roles for lipid rafts have been described for multiple signaling pathways in many contexts, their in vivo prevalence and role during embryonic development remains incompletely understood. Here we examined gene expression for the Raftlin family of lipid raft organizing proteins, Raftlin (RFTN1) and Raftlin-2 (RFTN2), over the course of early vertebrate development, with a focus on neural crest cell dynamics. By analyzing transcriptomic data across vertebrate species, we identified conserved patterns of RFTN1 and RFTN2 expression across species, where RFTN1 is broadly expressed at low levels, while RFTN2 is distinctly enriched in neural crest cells. We used fluorescent in situ hybridization to spatially define Raftlin gene expression patterns in the early avian embryo. Our results show that RFTN1 is broadly expressed with periods of enrichment in the developing paraxial mesoderm. In contrast, RFTN2 expression is strongly enriched in neural crest cells, beginning during specification and persisting through migration, with additional expression in both the cranial and intermediate mesoderm. Together, these patterns suggest that Raftlins may play important roles in regulating signaling during development with specific roles in somitogenesis and in neural crest and mesodermal cell migrations.